Lamp-holder.



H. C. L. HOLDEN.

LAMP HOLDER.

GATION FILED MAR.26,1914.

APPLl Patented Mar. 23, 1915.

UNITED STATES PATENT OFFICE.

HENRY CAPEL LOFFT HOLDEN, OF LONDON, ENGLAND, ASSIGNOB. TO THE UNITED MOTOR INDUSTRIES, LIMITED, OF LONDON, ENGLAND, A CORPORATION F GREAT BRITAIN.

Speclcation o1' Letters Patent.

LAMP-HOLDER.

Patented Mar. 23, 1915.

T0 all whom it may concern HOLDEN, colonel, R. A., retired, a subject of the King of England, residing at London, England, have invented new and useful Improvements in Lamp-Holders, of which the following is aqspecification.

This invenqon relates to bayonet socket holders for incandescent electric lamps, electric couplings and the like, and consists' of an improve contact devie for providing the electrical connection wigi the contact or contacts upon the cap of the lamp bulb or the like.

The invention is particularly intended for the sockets or holders used for incandescent lamps such as are employed in electric lighting for automobile vehicles; these lamps, .being of low voltage and comparatively high power, require a heavier current (i. e. of

reater ampeiage) than the lamps usually tted in bayonet socket holders. Forrr this reason the usual construction of sliding contact plungei', in which the current passes either through the spring or between the sliding surfaces themselves has proved unsatisfactory in operation.

According to the present invention. the w-irelor connection conveyingr the electric current extends as far as the actual contactdevice or plunger which presses upon the lamp cap plate or the like and it is sepa rated from the lamp' only by the said contact-device, against which it is firmly pressed.

.this plunger itself bearing evenly upon the lamp cap plate so as to insure definite and adequate contact with the latter. Preferably the contact device comprises a thmble having a screwed gland through which the electrical connection passes, the gland serving to compress the extremity of the eomieetion against the head of the thimble, and a Spring advancing the thimble outward into contact with the lamp cap or the like.

Upon the accompanying drawings which illustrate two forms of construction of the invention, Figure 1 is an elevation of the lamp holder with a bayonet-cap lamp fitted in place. Fig'. 2 is a section of the holder. Fig. 3 is a detail showing one method of connecting the wire or flexible cable to the thimble of the contact device. Fig. 4'is a sectional elevation of a vmodified construction, showing the parts slightly separated. Fig. 5 is an enlarged view ofthe connection employed in this modification. Fig. 6 is a sectional elevation of a complete electric lamp fitted with the invention.

The lamp holder illustrated b ample in the drawings is of the on-fpiece type, in which the insulatin base a is made integral with the head al, bein of porcelain or other suitable material. he brass or other casing or socket b may be forced upon the' base and secured by indentations c engaged in corresponding recesses or grooves upon the base.

The wires d d which convey the current pass through holes c e in the head, these holes being shouldered out at ,their inner end s el as seen in Fig. 2. T he larger bore is dcslgned to receive the internally threaded thiinble f forming the sliding portion of the contact device; it will be noted that this thimble is of larger diameter than the usual sliding contact pin. and that therefore a larger area of contact with the lamp cap inaythus be obtained. The extremity of the flexible wire (l is secured to this thiinble by means of a screwed bush or gland g serving to compress the twisted or balled extremity all of the conductor against the head of the thimble, as shown in section at the right of Fig. 2. The sliding thimblc f is shown pressed outward to make contact with the usual segments upon the bayonet cap ofthe lamp, by means of a helical spring j coiled around rthe wire and' abutting against a washer while its other end presses against the shoulder of the hole e el. At emerging from the head c1 of the socket or holder the connections may be secured b any suitable form of cord-grip, as desire the part o the connection within the holder is left sufiiciently loose to permit the required movement of the thimble f for making certain pontact withA the cap of the incandescentl amp.

Figs. 4 and 5 show a. modified construction in which the twisted extremity all 'of the lead is passedthrough anl e e f upon the inner end of the plunger. gland or cap g screws over this eye and thus conipletes the direct connection of the electricall lead d to the plunger. The glands g serve to limit the outward movement of the plungers; see Fig. 4.

Fig. 6 represents a lamp, such as the headlight of anrautomobile,fitted with the iniproved lamp-holder. The lamp-body l, in-

sof

closing the glow lamp m., has a front door or cover-glass n and a parabolic or othe re- Sector o. In the axis of the latter, the holder socket Z) is screwed into a bushing ,flr and locked by a nut b1. The multiple cable 1', containing the leads al d is clamped at the other end of the bushing by means of a clip s adapted to be tighened by a screw s1. The bushing g is slidable axially through the lamp for the purpose of focusing the lamp, and it may be locked in the desired position by a clamp t having va winged nut t1.

lt willbe understood that the invention is not limited to the details of construction shown and described, and that the improved Contact device may be applied `to bayonet socket holders 'for other than the iucandes cent lamps for lighting e. g. for heating lamps'or heating resistencias and the like, and also for other purposes, for example, for extension plugs, adapters and the like.

Other suitable forms of lamp holders may be employed with this improved contact device.

Having thus described my invention what I claim as such and desire to secure by Let ters Patent is z-n 1. In a lampliolder socket, the combination of an insulator, a plunger slldably mounted therein, and adapted to make con tact with a lamp-cap, means mounted on and adjustable relatively to the plunger for se. curing the lead Within the plunger, whereby the current is conducted directly to said plunger, and means for mechanically' connectingsaid lead to the socket.

2. In a lamp-holder socket, an insulator, a plunger slidable therein, said plunger vadapted to make Contact with a lamp-cap, means including a member adjustable on the plunger for securing the lead within the plunger whereby the current is conducted'directly to said plunger, and means for mechanically connecting said lead to the socket.

in a lampholder s( niet, an insulator, a plunger slidable therein, a spring tending to force said plunger outward into Contact with alamp-cap, means for fixing an ele-- trical lead to said socket, and means including a member engageable with and adjustable relatively to the plunger' for securing the lead within the plunger whereby the current is conducted directly to said plunger without passing through. said spring.

l, A bayonet socket lamp holder, comprising a socket, means for securing an electrical lead to said socket, an insulator, said insulator mounted in said socket, and a contact-device slidable in said insulator, said contact-device comprising a thimble, a screwed gland adjustable on the thimblo through which gland the electrical conncction passes, said gland serving to compress an extremity et' said electrical connection against an extremity oi' said. thirnble, and a spring advancing the thimblo outward into Contact with the lamp cap.

5. A buoyant-socket lamp holder, coni-- prising a socket, mechanical means for se curing said socket. to an electrical. lead, an insulator mounted in said socket, a plunger slidable in a longitudinal passage in said iesulator, a shoulder in said passage, an a`butment upon said lunger, a spring between said shoulder an said abutment, a screwed gland adjustable on the t'nimble and through which gland the electrical connection passes, said gland compressing an extremity of the electrical connection againstthe plunger and said spring advancing said plunger outward into contact i yith said lamp cap.

In testimony whereof I have alixed my signature 1n presence of two Witnesses.

HENR 4(JAPEL LOFFT HOLEEN. 

